<GridLayoutWidget>
    padding: 20
    spacing: 20
    cols: 3

    col_force_default: True
    col_default_width: 120
    row_force_default: True
    row_default_height: 40

    Button:
        text: "First"
        size_hint_x: None
        width: "100px"

    Button:
        text: "Second"

    Button:
        text: "Third"

    Button:
        text: "Fourth"